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Topic: 5.56 vs. .223 (Read 1762 times)

I own a Kel-Tec SU16CA. Company literature says it handles either 5.56 or .223 ammo. I recently ran across an article saying you should never fire 5.56 ammo in a .223 chamber, lest you risk destroying your weapon or yourself.

Is there any truth to this? Does this imply that the SU16 has a 5.56 chamber?

Remember, this is not my field of expertise. I know how to clean them, and shoot them. Much beyond that and I don't have a lot of interest. I know, heresy, but there it is.

Fortuna Fortis Paratus“In the house of a wise man are stores of food, wine, and oil, but the foolish man devours all he has.” Proverbs 21:20"We are content with discord, we are content with alarms, we are content with blood, but we will never be content with a master." -Pashtun malik, 1815

I have owned a mini-14 that in fact would not shoot 5.56. It was a target model that I sold about a year after the asinine "assault weapons" ban - for alot more than I bought it - thanks Slick Willy! The instructions were pretty adamant about NOT using 5.56 - my current mini-14 works just fine with 5.56 however.

Have you looked at any markings on the barrel/chamber area of the rifle itself?

Yes, it says .223 on the top of the receiver. I always assumed this meant it was chambered .223. Why 5.56 isn't a problem for this gun was not really explained by the person from Ruger. Only that firing either .223 or 5.56 was not anything to worry about.

This is a 580 series Mini 14. I don't know if this holds true for earlier versions.

BTW, I just saw this post on The View From Under The Desk about the effect of different rifling twist rates on the accuracy of different 5.56mm rounds. The Kel-Tec Web site states that the SU-16C has a barrel with a twist rate of 1:9, so it should be fine with pretty much any common 5.56mm/.223 Remington ammunition (with lead-core bullets in the 40-grain to 73-grain range).

American parachutists...devils in baggy pants...are less than 100 meters from my outpost line. I can't sleep at night; they pop up from nowhere and we never know when or how they will strike next. Seems like the black-hearted devils are everywhere....

From Wiki:While the 5.56mm NATO and .223 Remington cartridges and chamberings are very similar, they are not identical.

While there is a myth that 5.56 NATO cases are thicker and hence have less capacity than commercial .223 cases, this has been shown to be false. Each brand of case and each manufacturing lot has a slightly different case capacity; 5.56 NATO and .223 commercial cases tend to have nearly identical case capacity when measured using the water test.[6] The NATO specification allows a higher chamber pressure. NATO EPVAT test barrels made for 5.56mm NATO measure chamber pressure at the case mouth, as opposed to the location used by the United States civil standards organization SAAMI. The piezoelectric sensors or transducers NATO and SAAMI use to conduct the actual pressure measurements also differ. This difference in measurement method accounts for upwards of 137.9 megapascals (20,000 psi) difference in pressure measurements. This means the NATO EPVAT maximum service pressure of 430 megapascals (62,000 psi) for 5.56mm NATO, is reduced by SAAMI to 379.21 megapascals (55,000 psi) for .223 Remington.[7] In contrast to SAAMI, the other main civil standards organization C.I.P. defines the maximum service and proof test pressures of the .223 Remington cartridge equal to the 5.56mm NATO.

The 5.56mm NATO chambering, known as a NATO or mil-spec chamber, has a longer leade (also referred to as the throat), which is the distance between the mouth of the cartridge and the point at which the rifling engages the bullet. The .223 Remington chambering, known as SAAMI chamber, is allowed to have a shorter leade, and is only required to be proof tested to the lower SAAMI chamber pressure. To address these issues, various proprietary chambers exist, such as the Wylde chamber (Bill Wylde)[8] or the ArmaLite chamber, which are designed to handle both 5.56mm NATO and .223 Remington equally well. The dimensions and leade of the .223 Remington minimum C.I.P. chamber also differ from the 5.56mm NATO chamber specification.

Using commercial .223 Remington cartridges in a 5.56mm NATO chambered rifle should work reliably, but generally will not be as accurate as when fired from a .223 Remington chambered gun due to the longer leade.[9] Using 5.56mm NATO mil-spec cartridges (such as the M855) in a .223 Remington chambered rifle can lead to excessive wear and stress on the rifle and even be unsafe, and the SAAMI recommends against the practice.[10][11] Some commercial rifles marked as ".223 Remington" are in fact suited for 5.56mm NATO, such as many commercial AR-15 variants and the Ruger Mini-14, but the manufacturer should always be consulted to verify that this is acceptable before attempting it, and signs of excessive pressure (such as flattening or gas staining of the primers) should be looked for in the initial testing with 5.56mm NATO ammunition.[12]

Do I treat Glocks like I treat my lawn mowers? No, I treat them worse. I treat my defensive weapons like my fire extinguishers and smoke detector - annual maintenance and I expect them to work when needed

Fortuna Fortis Paratus“In the house of a wise man are stores of food, wine, and oil, but the foolish man devours all he has.” Proverbs 21:20"We are content with discord, we are content with alarms, we are content with blood, but we will never be content with a master." -Pashtun malik, 1815

Fortuna Fortis Paratus“In the house of a wise man are stores of food, wine, and oil, but the foolish man devours all he has.” Proverbs 21:20"We are content with discord, we are content with alarms, we are content with blood, but we will never be content with a master." -Pashtun malik, 1815